Influence of Echoes on Television Transmission
Pierre Mertz · Journal of the Society of Motion Picture and Television Engineers · 1953
Echoes in television transmission appear as irregularities in attenuation and phase characteristics. Tolerances on echoes well removed from the main picture are independent of the spacing (or echo delay). They vary inversely with spacing (echo delay) for close-up echoes. In the phase characteristic this leads to placing tolerances on envelope delay for large-scale features of the phase distortion, and on phase delay for fine structure irregularities. Tolerances are also placed upon the overall phase drift within the pass band. Similar treatment appears for the three classifications of attenuation distortion. Applications to broadcast and theater television are discussed.